JP7491206B2 - Control device, control method, computer program, and hydrogen production system - Google Patents

Description

The present disclosure relates to a control device, a control method, a computer program, and a hydrogen production system.

In recent years, hydrogen has been attracting attention as an energy source for reducing carbon _dioxide (CO2) emissions.

For example, Patent Document 1 discloses a control device that controls the input power to a hydrogen production device that produces hydrogen by receiving power generated by a solar power generator or the like and power supplied from a power grid.

International Publication No. 2020/121436

However, the control device described in Patent Document 1 aims to increase the reliability of power supply and demand adjustment for the hydrogen production device. As a result, there is an issue that it is not possible to control the amount of CO2 emissions during hydrogen production.

In particular, there is a global movement to classify hydrogen according to the amount of CO2 emissions during its production in order to move towards a decarbonized society, but the control device described in Patent Document 1 has difficulty producing hydrogen in accordance with this movement.

This disclosure has been made in light of these circumstances, and aims to provide a control device, control method, computer program, and hydrogen production system that enable efficient hydrogen production while reducing CO2 emissions during hydrogen production.

A control device according to one aspect of the present disclosure is a control device that controls a hydrogen production device that produces hydrogen using input power from a generator that uses renewable energy and power received from a power grid, and includes a target value acquisition unit that acquires a target value of carbon dioxide emissions during hydrogen production by the hydrogen production device, an emission acquisition unit that acquires carbon dioxide emissions in the production of the generated power and the received power, a generated power amount acquisition unit that acquires the amount of power generated by the generator, and a determination unit that determines the amount of power received from the power grid based on the target value, the amount of carbon dioxide emissions in the production of the generated power and the received power, and the generated power amount.

A control method according to another aspect of the present disclosure is a control method for controlling, by a computer, a hydrogen production device that produces hydrogen using input power generated by a generator that utilizes renewable energy and input power received from a power grid, the control method including a step of the computer acquiring a target value of carbon dioxide emissions during hydrogen production by the hydrogen production device, a step of the computer acquiring the amount of carbon dioxide emissions in the production of the generated power and the received power, a step of the computer acquiring the amount of power generated by the generator, and a step of the computer determining the amount of power received from the power grid based on the target value, the amount of carbon dioxide emissions in the production of the generated power and the received power, and the amount of power generated.

A computer program according to another aspect of the present disclosure is a computer program for causing a computer to function as a control device that controls a hydrogen production device that produces hydrogen using input power from a generator that uses renewable energy and power received from a power grid, and causes the computer to function as a target value acquisition unit that acquires a target value of carbon dioxide emissions during hydrogen production by the hydrogen production device, an emission acquisition unit that acquires carbon dioxide emissions in the production of the generated power and the received power, an amount of generated power acquisition unit that acquires the amount of power generated by the generator, and a determination unit that determines the amount of power received from the power grid based on the target value, the amount of carbon dioxide emissions in the production of the generated power and the received power, and the amount of generated power.

A hydrogen production system according to another aspect of the present disclosure includes a generator that uses renewable energy, a hydrogen production device that produces hydrogen using the power generated by the generator and the power received from a power grid as input power, and the above-mentioned control device that controls the hydrogen production device.

It goes without saying that the computer program can be distributed on a non-transitory computer-readable recording medium such as a CD-ROM (Compact Disc-Read Only Memory) or via a communication network such as the Internet. The present disclosure can also be realized as a semiconductor integrated circuit that realizes part or all of the control device.

This disclosure makes it possible to produce hydrogen efficiently while reducing CO2 emissions during hydrogen production.

FIG. 1 is a diagram showing an overall configuration of a hydrogen production system according to a first embodiment of the present disclosure. FIG. 2 is a block diagram illustrating a hardware configuration and a functional configuration of the control device according to the first embodiment of the present disclosure. FIG. 3 is a diagram illustrating an example of a screen display by a display control unit according to the first embodiment of the present disclosure. FIG. 4 is a flowchart illustrating an example of a processing procedure of the control device according to the first embodiment of the present disclosure. FIG. 5 is a diagram showing an overall configuration of a hydrogen production system according to a second embodiment of the present disclosure. FIG. 6 is a diagram showing the relationship between the amount of power P _{Bat — ac} (t) and the amount of power P _{Bat — dc} (t). FIG. 7 is a diagram illustrating an example of a screen display by a display control unit according to the second embodiment of the present disclosure. FIG. 8 is a flowchart illustrating an example of a processing procedure of the control device according to the second embodiment of the present disclosure.

[Summary of the embodiment of the present disclosure]
First, an overview of the embodiments of the present disclosure will be listed and described.
(1) A control device according to one embodiment of the present disclosure is a control device that controls a hydrogen production device that produces hydrogen using input power generated by a generator that uses renewable energy and power received from a power grid, and includes a target value acquisition unit that acquires a target value of carbon dioxide emissions during hydrogen production by the hydrogen production device, an emission acquisition unit that acquires carbon dioxide emissions in the production of each of the generated power and the received power, a generated power amount acquisition unit that acquires the amount of power generated by the generator, and a determination unit that determines the amount of power received from the power grid based on the target value, the carbon dioxide emissions in the production of each of the generated power and the received power, and the generated power amount.

According to this configuration, the amount of received power input to the hydrogen production device is determined based on the target value of carbon dioxide (CO2) emissions, the amount of carbon dioxide emissions in the production of generated power and received power, and the amount of power generated by a generator that uses renewable energy. This makes it possible to determine the amount of carbon dioxide emissions during hydrogen production in accordance with the target value while achieving a good balance between the use of generated power and received power. This enables efficient hydrogen production while reducing the amount of carbon dioxide emissions during hydrogen production.

(2) Preferably, the determination unit determines the amount of received power by optimizing a predetermined objective function under the constraint that the sum of the carbon dioxide emissions in the production of the generated power and the received power input to the hydrogen production device does not exceed the target value.

With this configuration, a specified objective function can be optimized while preventing the amount of carbon dioxide emissions in the production of input power to the hydrogen production device from exceeding a target value. For example, by optimizing the objective function to maximize the amount of hydrogen produced, efficient hydrogen production can be achieved while reducing the amount of carbon dioxide emissions during hydrogen production.

(3) More preferably, the control device further controls a storage battery that charges the generated power and the received power, the emission amount acquisition unit further acquires the amount of carbon dioxide emissions in the production of the charging power for the storage battery, and the determination unit determines the amount of received power based on the target value, the amount of carbon dioxide emissions in the production of the generated power, the received power, and the charging power, respectively, and the amount of generated power.

With this configuration, even in a configuration with a storage battery, it is possible to determine the amount of carbon dioxide emissions during hydrogen production according to a target value while making good use of generated power and received power in a balanced manner.

(4) The emission amount acquisition unit may also calculate the amount of carbon dioxide emissions in the production of electricity charged to the storage battery in a state after the storage battery has been charged, based on the amount of carbon dioxide emissions in the production of electricity charged to the storage battery in a state before the storage battery has been charged and the amount of carbon dioxide emissions in the production of electricity to be charged to the storage battery.

With this configuration, even when the storage battery is charged with both generated and received power, it is possible to accurately calculate the amount of carbon dioxide emissions involved in the production of the electricity being charged into the storage battery.

(5) The control device may further include a display control unit that displays on a screen the ratio of carbon dioxide emissions in the production of electricity consumed in hydrogen production by the hydrogen production device relative to the target value.

This configuration makes it possible to know the percentage of carbon dioxide emitted during hydrogen production.

(6) The display control unit may further cause the generated power and the received power input to the hydrogen production device to be displayed on the screen.

This configuration makes it possible to know how much generated and received power is being used to produce hydrogen.

(7) The display control unit may also cause the screen to display the amount of carbon dioxide emissions in the production of the generated electricity and the received electricity.

According to this configuration, the amount of carbon dioxide emissions in the production of the generated power and the received power are displayed on the screen along with the values of the generated power and the received power. This makes it possible to know the amount of carbon dioxide emissions in the production of hydrogen. For example, by multiplying the value of the received power by the amount of carbon dioxide emissions in the production of the received power, it is possible to know the amount of carbon dioxide emissions in the production of hydrogen using the received power.

(8) A control method according to another embodiment of the present disclosure is a control method for controlling, by a computer, a hydrogen production device that produces hydrogen using input power generated by a generator that utilizes renewable energy and input power received from a power grid, the control method including the steps of: the computer acquiring a target value for carbon dioxide emissions during hydrogen production by the hydrogen production device; the computer acquiring the amount of carbon dioxide emissions in the production of the generated power and the received power; the computer acquiring the amount of power generated by the generator; and the computer determining the amount of power received from the power grid based on the target value, the amount of carbon dioxide emissions in the production of the generated power and the received power, and the amount of power generated.

This configuration includes steps that are characteristic of the control device described above. Therefore, it is possible to achieve the same effects and advantages as the control device described above.

(9) A computer program according to another embodiment of the present disclosure is a computer program for causing a computer to function as a control device that controls a hydrogen production device that produces hydrogen using input power from a generator that uses renewable energy and power received from a power grid, and causes the computer to function as a target value acquisition unit that acquires a target value of carbon dioxide emissions during hydrogen production by the hydrogen production device, an emission acquisition unit that acquires carbon dioxide emissions in the production of the generated power and the received power, an amount of generated power acquisition unit that acquires the amount of power generated by the generator, and a determination unit that determines the amount of power received from the power grid based on the target value, the amount of carbon dioxide emissions in the production of the generated power and the received power, and the amount of generated power.

With this configuration, the computer can function as the control device described above. This allows it to achieve the same effects and advantages as the control device described above.

(10) A hydrogen production system according to another embodiment of the present disclosure includes a generator that uses renewable energy, a hydrogen production device that produces hydrogen using the power generated by the generator and the power received from a power grid as input power, and the above-mentioned control device that controls the hydrogen production device.

This configuration includes the control device described above. Therefore, it can achieve the same effects and advantages as the control device described above.

[Details of the embodiment of the present disclosure]
Hereinafter, the embodiments of the present disclosure will be described with reference to the drawings. Note that each of the embodiments described below shows a specific example of the present disclosure. The numerical values, shapes, materials, components, arrangement and connection forms of the components, steps, and order of steps shown in the following embodiments are examples and do not limit the present disclosure. In addition, among the components in the following embodiments, components that are not described in the independent claims are components that can be added arbitrarily. In addition, each figure is a schematic diagram and is not necessarily illustrated strictly.

The same components are given the same symbols. Their functions and names are also the same, so their explanations will be omitted as appropriate.

<Embodiment 1>
[Overall configuration of hydrogen production system]
FIG. 1 is a diagram showing an overall configuration of a hydrogen production system according to a first embodiment of the present disclosure.

The hydrogen production system 1 is composed of equipment arranged in a power supply area 2, a piping area 3, a hydrogen production area 4, and a control area 5. However, each area may be the same area as another area, or may be an overlapping area.

A solar power generator 21, a DC/DC converter 22, a DC/AC converter 24, and an external I/F device 25 are installed in the power supply area 2.

The solar power generator 21 is an example of a renewable energy generator that generates electricity using renewable energy, and converts solar energy into direct current electricity. In this embodiment, an example of using the solar power generator 21 as a renewable energy generator is described, but other renewable energy generators such as wind power generators may be used instead of or together with the solar power generator 21.

The DC/DC converter 22 is connected to the solar power generator 21 via a power line, converts the voltage of the output power of the solar power generator 21, and outputs the converted power.

The DC/AC converter 24 is connected to the DC/DC converter 22 via a power line. The DC/AC converter 24 converts the DC power output from the DC/DC converter 22 into AC power and outputs it.

The external I/F device 25 is connected to each piece of equipment (solar power generator 21, DC/DC converter 22, and DC/AC converter 24) installed in the power supply area 2 via a communication line (not shown). The external I/F device 25 is a device for connecting each piece of equipment to a device outside the power supply area 2, and transmits data acquired from each piece of equipment to the external device and provides data received from the external device to each piece of equipment. For example, the external I/F device 25 acquires output power information indicating the output of the solar power generator 21 from the solar power generator 21, and transmits the acquired output power information to a control device 51 (described later) installed in the control area 5.

Valves 31, 33 and 34, a hydrogen storage tank 32 and an external I/F device 35 are installed in the piping area 3.

Valve 31 is a water supply valve installed midway along the water supply pipe, and adjusts the amount of water supplied to the hydrogen production device 42 (described later) installed in the hydrogen production area 4. The more the valve 31 is opened, the more water is supplied to the hydrogen production device 42, and the more the valve 31 is closed, the more the amount of water supplied to the hydrogen production device 42 is restricted.

The hydrogen storage tank 32 is connected to the hydrogen production device 42 via a hydrogen pipe and is a tank that stores hydrogen generated by the hydrogen production device 42. The hydrogen storage tank 32 is, for example, a tank that compresses hydrogen at high pressure and stores it. However, the method of storing hydrogen using the hydrogen storage tank 32 is not limited to this. The hydrogen storage tank 32 may be, for example, a tank that liquefies hydrogen at a low temperature and stores it. The hydrogen storage tank 32 may also be a tank that stores hydrogen by absorbing it into a hydrogen storage alloy, or a tank that stores hydrogen by adsorbing it into carbon nanotubes or the like. The hydrogen storage tank 32 may also be a tank that converts hydrogen into another substance and stores it, such as by reacting hydrogen with toluene to convert it into methylcyclohexane.

Valve 33 is a hydrogen supply valve installed midway along the hydrogen conduit, and adjusts the amount of hydrogen generated by hydrogen production device 42 stored in hydrogen storage tank 32. The more valve 33 is opened, the more hydrogen is stored in hydrogen storage tank 32, and the more valve 33 is closed, the more the amount of hydrogen stored in hydrogen storage tank 32 is limited.

The valve 34 is connected midway through a hydrogen conduit that branches off from the hydrogen conduit that connects the hydrogen production device 42 and the hydrogen storage tank 32, and adjusts the amount of hydrogen generated by the hydrogen production device 42 that is released into the atmosphere. By opening the valve 34, a larger amount of hydrogen is released into the atmosphere, and the more the valve 34 is closed, the more the amount of hydrogen released into the atmosphere is limited.

The external I/F device 35 is connected to each piece of equipment (valve 31, valves 33 and 34, hydrogen storage tank 32) installed in the piping area 3 via communication lines (not shown). The external I/F device 35 is a device for connecting each piece of equipment to a device outside the power supply area 2, and transmits data acquired from each piece of equipment to the external device and provides data received from the external device to each piece of equipment. For example, the external I/F device 35 acquires hydrogen storage amount information from the hydrogen storage tank 32 and transmits the acquired storage amount information to a control device 51 installed in the control area 5. The external I/F device 35 also receives command data on the opening/closing amount of the valve 31 from the control device 51 and provides the received command data to the valve 31. This controls the opening/closing amount of the valve 31.

The hydrogen production area 4 is equipped with an AC/DC converter 41, a hydrogen production device 42, a valve 43, and an external I/F device 44.

The AC/DC converter 41 is connected to the DC/AC converter 24 installed in the power supply area 2 via a power line, and converts the AC power output from the DC/AC converter 24 into DC power and outputs it. The AC/DC converter 41 is also connected to the power grid 6, receives power from the power grid 6, converts the received power into DC power and outputs it. In other words, the AC/DC converter 41 converts a mixture of the AC power output from the DC/AC converter 24 and the power received from the power grid 6 into DC power and outputs it.

The hydrogen production device 42 electrolyzes water supplied from the piping area 3 into hydrogen and oxygen using DC power output from the AC/DC converter 41, and extracts hydrogen. The hydrogen production device 42 employs, for example, a solid polymer water electrolysis method, which generates oxygen and hydrogen ions by supplying water to the positive electrode side, and generates hydrogen by passing the hydrogen ions through a fluororesin cationic membrane or the like and moving them to the negative electrode side. However, the water electrolysis method is not limited to the above. Other methods such as alkaline water electrolysis and high-temperature steam electrolysis may also be used as the water electrolysis method. The hydrogen production device 42 may also generate hydrogen using a method other than water electrolysis, such as toluene electrolytic reduction. In the case of the toluene electrolytic reduction method, toluene is used instead of water.

The number of hydrogen production devices 42 is not limited to one, and multiple devices may be installed in the hydrogen production area 4.

The valve 43 is a hydrogen supply valve that is installed midway in the hydrogen conduit that connects the corresponding hydrogen production device 42 and the hydrogen storage tank 32, and adjusts the amount of hydrogen output generated by the hydrogen production device 42. By opening the valve 43, a larger amount of hydrogen is output from the hydrogen production device 42, and by closing the valve 43, the amount of hydrogen output from the hydrogen production device 42 is limited.

The external I/F device 44 is connected to each piece of equipment (AC/DC converter 41, hydrogen production device 42, and valve 43) installed in the hydrogen production area 4 via a communication line (not shown). The external I/F device 44 is a device for connecting each piece of equipment to a device outside the hydrogen production area 4, and transmits data acquired from each piece of equipment to the external device and provides data received from the external device to each piece of equipment. For example, the external I/F device 44 acquires hydrogen generation amount information from the hydrogen production device 42 and transmits the acquired hydrogen generation amount information to the control device 51 installed in the control area 5. The external I/F device 44 also receives command data for starting and stopping the hydrogen production device 42 from the control device 51 and provides the received command data to the hydrogen production device 42. This controls the start and stop of the hydrogen production device 42.

A control device 51 is installed in the control area 5.

The control device 51 is connected to the external I/F devices 25, 35, and 44 installed in each area via communication lines. The control device 51 acquires various information on the equipment installed in each area from the external I/F devices 25, 35, and 44. The control device 51 controls each equipment via the external I/F devices 25, 35, and 44 based on the acquired information. The control device 51 also monitors the amount of power at the power receiving point 7 from the power system 6 using a watt-hour meter or the like.

In particular, the control device 51 determines the value of the received power from the power grid 6 to be input to the hydrogen production device 42 based on the target value of carbon dioxide (hereinafter referred to as CO2) emissions, the CO2 emissions in the production of the power generated by the solar power generator 21 and the power received from the power grid 6, and the amount of power generated by the solar power generator 21. The control device 51 controls the input power to the hydrogen production device 42 so that the received power at the power receiving point 7 matches the determined value of the received power.

The control device 51 also displays the operating status of the hydrogen production system 1 on the display device 52. Display examples of the display device 52 will be described later.

[Configuration of the control device 51]
FIG. 2 is a block diagram showing a hardware configuration and a functional configuration of the control device 51 according to the first embodiment of the present disclosure.
The control device 51 includes a control unit 53 , a communication unit 54 , and a memory unit 55 .

The control unit 53 includes a CPU (Central Processing Unit) and is provided with a target value acquisition unit 56, an emission amount acquisition unit 57, a generated power amount acquisition unit 58, a determination unit 59, a command transmission unit 60, and a display control unit 61 as functional processing units realized by executing a computer program previously stored in the memory unit 55.

The communication unit 54 is composed of a communication device that executes communication processing with the external I/F devices 25, 35, and 44. In other words, the communication unit 54 transmits information provided by the control unit 53 to the external I/F devices 25, 35, and 44 via the communication line, and provides information received from the external I/F devices 25, 35, and 44 via the communication line to the control unit 53.

The storage unit 55 is composed of a volatile memory element such as SRAM (Static Random Access Memory) or DRAM (Dynamic Random Access Memory), a non-volatile memory element such as flash memory or EEPROM (Electrically Erasable Programmable Read-Only Memory), or a magnetic storage device such as a hard disk. The storage unit 55 stores the computer programs executed by the control unit 53 and data necessary for their execution.

The target value acquisition unit 56 acquires a target value for the amount of CO2 emissions during hydrogen production by the hydrogen production device 42. Specifically, the target value acquisition unit 56 reads out from the storage unit 55 a base CO2 emission amount CO2 _Base [kg/ ^Nm3 ] and a CO2 tolerance rate CO2 _Rate [%/100] that are stored in advance in the storage unit 55 as target values.

The CO2 emission amount CO2 _Base indicates, for example, the weight [kg] of CO2 generated when ¹ Nm3 of hydrogen is produced by reforming natural gas.

The CO2 tolerance rate CO2 _Rate indicates the tolerance rate of CO2 emissions by the hydrogen production device 42 when the CO2 emissions CO2 _Base is used as a reference. In other words, the value obtained by multiplying the CO2 tolerance rate CO2 _Rate by the CO2 emissions CO2 _Base (CO2 _Rate × CO2 _Base ) indicates the target value for the weight [kg] of CO2 generated when ¹ Nm3 of hydrogen is produced by the hydrogen production device 42.

The emission amount acquisition unit 57 acquires the CO2 emission amounts in the production of the power generated by the solar power generator 21 and the power received from the power grid 6. Specifically, the emission amount acquisition unit 57 reads out from the storage unit 55 the CO2 emission amount CO2 _Pv (t) [kg/kWh] in the production of the power generated by the solar power generator 21 and the CO2 emission amount CO2 _Grid (t) [kg/kWh] in the production of the power received from the power grid 6, which are stored in advance in the storage unit 55. Here, t indicates a target period, for example, a period in units of 30 minutes.

The generated power amount acquiring unit 58 acquires the amount of power generated by the solar power generator 21. Specifically, the generated power amount acquiring unit 58 reads out from the storage unit 55 the amount of power generated by the solar power generator 21 P _Pv (t) [kWh] that is stored in advance in the storage unit 55.

The determination unit 59 determines the amount of power received from the power grid 6, P _Grid (t) [kWh], based on the target values of CO2 emission amounts (CO2 _Base , CO2 _Rate ), the CO2 emission amounts CO2 _Pv (t) and CO2 _Grid (t), and the amount of power generated, P _Pv (t).

Hereinafter, a method for determining the amount of received power P _Grid (t) [kWh] by the determination unit 59 will be described in more detail.

The determination unit 59 determines the amount of received power P Grid (t) from the power grid 6 by optimizing a predetermined objective function under the constraint that the total amount of CO2 emissions in the production of generated power and received power input to the hydrogen production device 42 does not exceed the target value of _CO2 emissions.

For example, the determination unit 59 determines the amount of power received from the power grid 6 P _Grid (t) by maximizing the objective function shown in Equation 1 under the constraint conditions shown in the following Equations 14 to 18. A predetermined mathematical optimization method is used to determine the amount of power received P _Grid (t).

Next, each formula will be explained.
<<Objective function>>
Hydrogen production amount [Nm ³ ]: Maximization of Total _H2 (t _max ) (Equation 1)
Equation 1 shows the objective function optimized by the determination unit 59. Here, the objective function is to maximize the total amount of _hydrogen produced by the hydrogen production device 42 from 0 to _tmax .

<<Parameters>>
Power generation amount (predicted value) [kWh] of the solar power generator 21: P _Pv (t) ... (Equation 2)
CO2 emissions from grid power [kg/kWh]: CO2 _Grid (t) ... (Equation 3)
CO2 emission amount from the solar power generator 21 [kg/kWh]: CO2 _Pv (t) ... (Equation 4)
Standard CO2 emission amount [kg/ ^Nm3 ]: CO2 _Base ... (Equation 5)
CO2 tolerance rate [% / 100]: CO2 _Rate ... (Equation 6)
Hydrogen production efficiency [Nm ³ /kWh]: ξ ... (Equation 7)
Rated input power of the hydrogen production device 42 [kWh]: P _{WE_rate} ... (Equation 8)

Equations 2 to 8 show the parameters required to calculate the objective function or the constraints described below.

Equation 2 shows the power generation amount P _Pv (t) [kWh] of the solar power generator 21 in the target period t acquired by the power generation amount acquisition unit 58. The power generation amount P _Pv (t) is a predicted value based on meteorological information such as the weather and temperature on the day, for example.

Equation 3 shows the amount of CO2 emissions CO2 _Grid (t) [kg/kWh] in the production of power received from the power grid 6 during the target period t, which is acquired by the emission amount acquisition unit 57.

Equation 4 shows the amount of CO2 emissions CO2 _Pv (t) [kg/kWh] in the production of power generated by the solar power generator 21 during the target period t, acquired by the emission amount acquisition unit 57.

Equation 5 represents the base CO2 emission amount CO2 _Base [kg/Nm ³ ] acquired by the target value acquisition unit 56 .

Equation 6 represents the CO2 tolerance rate CO2 _Rate [%/100] acquired by the target value acquisition unit 56.

The hydrogen production efficiency ξ shown in Equation 7 indicates the amount of hydrogen produced [Nm ³ ] per kWh of input power to the hydrogen production device 42 .

Equation 8 represents the rated input power P _{WE — rate} [kWh] of the hydrogen production device 42 .

The values of equations 7 and 8 are stored in advance in memory unit 55, and determination unit 59 reads these values from memory unit 55.

<<Variables>>
Target period: t [0, 1, ..., tmax] ... (Equation 9)
Received power amount [kWh]: P _Grid (t) ... (Equation 10)
Input power amount of the hydrogen production device 42 [kWh]: _PWE (t) ... (Equation 11)
Total CO2 emissions during hydrogen production [kg]: Total _co2 (t) ... (Equation 12)
Hydrogen production amount [Nm ³ ]: Total _H2 (t) ... (Equation 13)

Equations 9 to 13 show the variables used when calculating the objective function or constraints.

Equation 9 is a variable that represents the target period t, where t indicates a period from 0 to tmax, which is tmax+1. Each period is, for example, 30 minutes that corresponds to the demand time limit. However, the length of the period is not limited to 30 minutes.

Equation 10 shows the amount of power received from the power grid 6 during the target period t, P _Grid (t) [kWh].

Equation 11 shows the amount of input power P _WE (t) [kWh] to the hydrogen production device 42 during the target period t.

Equation 12 shows the total CO2 emission amount Total _co2 (t) [kg] during hydrogen production by the hydrogen production device 42 from the target period 0 to the target period t.

Equation 13 shows the amount of hydrogen produced [Nm ³ ] by the hydrogen production device 42 from the target period 0 to the target period t.

<<Constraints>>
P _Grid (t) + P _Pv (t) = P _WE (t) ... (Equation 14)
Total _co2 (t) = Total _co2 (t-1)
+ CO2 _Grid (t-1) x P _Grid (t-1)
+ CO2 _Pv (t-1) × P _Pv (t-1) ... (Equation 15)
Total _H2 (t) = Total _H2 (t-1) + _PWE (t-1) × ξ
... (Equation 16)
CO2 _Base × CO2 _Rate ≧ Total _CO2 (t _max ) / Total _H2 (t _max ) ... (Equation 17)
_PWE (t)≦ _{PWE_rate} (Formula 18)

Equations 14 to 18 show the constraints for maximizing the objective function shown in equation 1.

Equation 14 shows that the sum of the amount of power received from the power grid 6 during the target period t P _Grid (t) and the amount of power generated by the solar generator 21 during the target period t P _Pv (t) is equal to the amount of power input P _WE (t) to the hydrogen production device 42 during the target period t.

Equation 15 shows that the total CO2 emissions from target period 0 to target period t, Total _co2 (t), is equal to the total CO2 emissions from target period 0 to target period t-1, Total _co2 (t-1), plus the CO2 emissions in the production of received electricity from the power grid 6, CO2 _Grid (t-1) × P _Grid (t-1), and the CO2 emissions in the production of generated electricity by the solar power generator 21, CO2 _Pv (t-1) × P _Pv (t-1).

Equation 16 shows that the amount of hydrogen produced from the target period 0 to t, Total _H2 (t), is equal to the amount of hydrogen produced from the target period 0 to t-1, Total _H2 (t-1), multiplied by the input power _PWE (t-1) and the hydrogen production efficiency ξ.

Equation 17 shows that the CO2 emissions per ¹ Nm3 during hydrogen production from 0 to tmax, Total _co2 (t _max )/Total _H2 (t _max ), is less than the target value CO2 _Base × CO2 _Rate of the weight [kg] of CO2 generated when ¹ Nm3 of hydrogen is produced by the hydrogen production device 42.

Equation 18 indicates that the input electric power P _WE (t) of the hydrogen production device 42 in the target period t is equal to or less than the rated input electric power P _{WE_rate} of the hydrogen production device 42 .

1 and 2 again, the command transmitting unit 60 monitors the amount of power flowing through the power receiving point 7, and determines the amount of input power _PWE (t) to the hydrogen production device 42 according to Equation 14 so that the amount of power matches the amount of received power _PGrid (t) determined by the determining unit 59. The command transmitting unit 60 transmits a command including the amount of input power _PWE (t) to the external I/F device 44. The external I/F device 44 receives a command from the command transmitting unit 60, and controls the amount of input power to the hydrogen production device 42 during the target period t so that the amount of input power matches the amount of input power _PWE (t) indicated by the command.

The display control unit 61 causes the screen of the display device 52 to display the ratio of CO2 emissions in the production of electricity consumed in hydrogen production by the hydrogen production device 42 (input electricity to the hydrogen production device 42) to the target value of CO2 emissions (hereinafter referred to as the reference CO2 emission ratio). The display control unit 61 also causes the screen of the display device 52 to display the generated electricity and received electricity input to the hydrogen production device 42. The display control unit 61 also causes the screen of the display device 52 to display the CO2 emissions in the production of the generated electricity and received electricity, respectively.

Figure 3 is a diagram showing an example of a screen display by the display control unit 61 according to the first embodiment of the present disclosure.

For example, in graph 71, the standard CO2 emission rate of hydrogen produced by the hydrogen production device 42 is shown by a hatched area, and the CO2 tolerance rate CO2 _Rate [%/100] is shown as a percentage to be 40%. Also, the amount of CO2 emissions generated during hydrogen production by the hydrogen production device 42 is shown to be AAA [kg/ ^Nm3 ], and the standard CO2 emission rate is shown as 35 [%].

In addition, in the graph 72, the hatched area indicates the ratio of hydrogen stored in the hydrogen storage tank 32. Also, the amount of hydrogen produced is indicated by a numerical value: NNN [Nm ³ ].

It also shows that the received power from the power grid 6 that is input to the hydrogen production device 42 is P [kW], and the generated power of the solar power generator 21 that is input to the hydrogen production device 42 is Q [kW]. It also shows that the input power of the hydrogen production device 42 is W [kW].

It also shows that the amount of CO2 emissions in the production of electricity received from the power grid 6 is xxx [kg/kWh]. It also shows that the amount of CO2 emissions in the production of electricity generated by the solar power generator 21 is yyy [kg/kWh].

[Processing flow of the control device 51]
FIG. 4 is a flowchart showing an example of a processing procedure of the control device 51 according to the first embodiment of the present disclosure.

The target value acquisition unit 56 reads out the target values of the CO2 emission amount (CO2 _Base , CO2 _Rate ) from the storage unit 55 (S1).

The emission acquisition unit 57 reads out the CO2 emission amount CO2 _Grid (t) in the production of the received power from the power grid 6 from the storage unit 55 (S2).

The emission acquisition unit 57 reads out the CO2 emission amount CO2 _Pv (t) in the production of the power generated by the solar power generator 21 from the storage unit 55 (S3).

The generated power amount acquisition unit 58 reads out the generated power amount P _Pv (t) of the solar power generator 21 from the storage unit 55 (S4).

The determination unit 59 determines the amount of power received from the power grid 6 P _Grid (t) by maximizing the objective function shown in Equation 1 under the constraint conditions shown in Equations 14 to 18 (S5).

The command transmitting unit 60 determines the amount of input power _PWE (t) to the hydrogen production device 42 based on the amount of received power _PGrid (t), and transmits a command including the amount of input power _PWE (t) to the external I/F device 44 (S6).

[Effects of the First Embodiment]
As described above, according to the first embodiment of the present disclosure, the amount of received power to be input to the hydrogen production device 42 is determined based on the target value of CO2 emissions, the CO2 emissions in the production of power generated by the solar power generator 21 and power received from the power grid 6, and the amount of power generated by the solar power generator 21. This makes it possible to determine the amount of CO2 emissions during hydrogen production in accordance with the target value while making well-balanced use of the generated power and the received power. This enables efficient hydrogen production while reducing the amount of CO2 emissions during hydrogen production.

Furthermore, the determination unit 59 determines the amount of power received from the power grid 6 by optimizing a predetermined objective function under the constraint that the sum of the CO2 emissions in the production of the generated power and the received power input to the hydrogen production device 42 does not exceed the target value for CO2 emissions. This makes it possible to optimize the predetermined objective function while preventing the CO2 emissions in the production of the power input to the hydrogen production device 42 from exceeding the target value. For example, by optimizing the objective function to maximize the amount of hydrogen production, efficient hydrogen production is possible while reducing the CO2 emissions during hydrogen production.

In addition, the display control unit 61 causes the display device 52 to display the standard CO2 emission ratio relative to the target value of the CO2 emission amount. This allows the user to know the percentage of CO2 being emitted during hydrogen production.

The display control unit 61 also displays the generated power and received power input to the hydrogen production device 42 on the screen of the display device 52. This allows the user to know how much generated power and received power is being used to produce hydrogen.

The display control unit 61 also causes the screen of the display device 52 to display the amount of CO2 emissions in the production of the generated power and the received power. That is, the amount of CO2 emissions in the production of the generated power and the received power are displayed on the screen along with the values of the generated power and the received power. This allows the user to know the amount of CO2 emissions in the production of hydrogen. For example, by multiplying the value of the received power by the amount of CO2 emissions in the production of the received power, the user can know the amount of CO2 emissions in the production of hydrogen using the received power.

<Modification 1>
In the above embodiment, the determination unit 59 determines the amount of received electric power P _Grid (t) by maximizing the amount of hydrogen production (Equation 1), but the objective function is not limited to that shown in Equation 1. For example, a sub-objective function shown in the following Equation 19 or Equation 20 may be used as the objective function.

The determination unit 59 determines the amount of power received from the power grid 6 P Grid (t) by optimizing _the sub-objective function shown in Equation 19 or Equation 20 under the constraint conditions shown in Equations 14 to 18 and the sub-constraint conditions shown in the following Equations 31 to 39.

Next, each formula will be explained.
<<Sub-objective functions>>
Total hydrogen production cost [yen]: Minimization of TotalCost _H2 (t _max )...(Equation 19)
Operation rate [%/100] of the hydrogen production device 42: Maximization of TotalRate (t _max )
... (Equation 20)

Equation 19 shows the objective function optimized by the determination unit 59. Here, the optimization of the objective function is to minimize the total hydrogen production cost TotalCost _H2 (t _max ) by the hydrogen production device 42 from the target period 0 to tmax.

Equation 20 shows the objective function that the determination unit 59 optimizes. Here, the objective function is optimized to maximize the operation rate TotalRate(t _max ) of the hydrogen production device 42 from 0 to tmax in the target period.

<<Sub-parameters>>
System power unit price [yen/kWh]: Cost (t) ... (Equation 21)
Tank capacity upper limit [Nm ³ ]: T _HL ... (Equation 22)
Tank capacity lower limit [Nm ³ ]: T _LL ... (Equation 23)
Upper limit of operation rate of hydrogen production device 42 [%/100]: R _HL (Equation 24)
Lower limit of operation rate of hydrogen production device 42 [%/100]: R _LL ... (Equation 25)

Equations 21 to 25 show the parameters required to calculate the sub-objective functions or sub-constraints.

Equation 21 shows the grid power unit cost Cost(t) [yen/kWh], which is the unit price of power received from the power grid 6 during the target period t.

Equation 22 shows the tank capacity upper limit T _HL [Nm ³ ], which is the upper limit of the capacity of the hydrogen storage tank 32 .

Equation 23 represents the tank capacity lower limit T _LL [Nm ³ ], which is the lower limit of the capacity of the hydrogen storage tank 32 .

Equation 24 represents the upper limit R _HL [%/100] of the operation rate of the hydrogen production device 42 .

Equation 25 represents the lower limit R _LL [%/100] of the operation rate of the hydrogen production device 42 .

The values of equations 21 to 25 are stored in advance in the memory unit 55, and the determination unit 59 reads these values from the memory unit 55.

<<Sub variable>>
Hydrogen storage tank remaining capacity [Nm ³ ]: TANK(t) (Equation 26)
Purchased electricity cost [yen]: TotalCost _Grid (t) ... (Equation 27)
Total input power of the hydrogen production device 42 [kWh]: TatalP _WE (t) ... (Equation 28)
Total hydrogen production cost [yen]: TotalCost _H2 (t) ... (Equation 29)
Operating rate of hydrogen production device 42 [%/100]: TotalRate(t) ... (Equation 30)

Equations 26 to 30 show the variables used when calculating the sub-objective functions or sub-constraints.

Equation 26 shows the remaining amount TANK(t) [Nm ³ ] of the hydrogen storage tank 32 during the target period t.

Equation 27 shows the amount of electricity purchased from the power grid 6 from the target period 0 to the target period t, _{TotalCostGrid} (t) [yen].

Equation 28 shows the total input power TatalP _WE (t) [kWh] of the hydrogen production device 42 from the target period 0 to the target period t.

Equation 29 shows the total cost TotalCost _H2 (t) [yen] required for hydrogen production by the hydrogen production device 42 from the target period 0 to the target period t.

Equation 30 shows the operating rate TotalRate(t) [%/100] of the hydrogen production device 42 from the target period 0 to the target period t.

<<Sub-constraint conditions>>
_{TotalCostGrid} (t)= _{TotalCostGrid} (t-1)
+Cost(t-1)×P _Grid (t-1) ... (Equation 31)
TotalCost _H2 (t)=TotalCost _H2 (t−1)
+Cost(t-1) x P _Grid (t-1)
... (Equation 32)
TotalRate(t)= _TatalPWE (t)
/(t × _{PWE_rate} ) ... (Equation 33)
TANK(t)=TANK(t−1)+ _PWE (t−1)×ξ (Equation 34)
TANK(t)≧ _TLL (Equation 35)
TANK(t)≦ _THL (Equation 36)
Tat _alPWE (t) = Tat _alPWE (t-1) + _PWE (t-1)
... (Equation 37)
TotalRate(t _max )≧R _LL ... (Equation 38)
TotalRate(t _max )≦R _HL ... (Equation 39)

Equations 31 to 39 show the constraints for optimizing the sub-objective function shown in equation 19 or equation 20.

Equation 31 shows that the amount of electricity purchased from the power grid 6 from the target period 0 to the target period t, TotalCost _Grid (t), is equal to the amount of electricity purchased from the power grid 6 from the target period 0 to the target period t-1, TotalCost _Grid (t-1), added to the product of the system electricity unit price Cost(t-1) and the amount of electricity received from the power grid 6, P _Grid (t-1).

Equation 32 shows that the total hydrogen production cost TotalCost _H2 (t) from target period 0 to target period t is equal to the total hydrogen production cost TotalCost _H2 (t-1) from target period 0 to target period t-1 added to the product of the grid electricity unit price Cost(t-1) and the amount of electricity received from the power grid 6 P _Grid (t-1).

Equation 33 shows that the operating rate TotalRate(t) of the hydrogen production device 42 from target period 0 to target period t is equal to the total input power of the hydrogen production device 42 from target period 0 to target period t divided by the product of target period t and the rated input power _{PWE_rate} of the hydrogen production device 42.

Equation 34 shows that the hydrogen storage tank remaining capacity TANK(t) during the target period t is equal to the hydrogen storage tank remaining capacity TANK(t-1) during the target period t-1 plus the multiplied value of the input power _PWE (t-1) of the hydrogen production device 42 and the hydrogen production efficiency ξ.

Equation 35 indicates that the hydrogen storage tank remaining amount TANK(t) during the target period t is equal to or greater than the tank capacity lower limit _TLL .

Equation 36 shows that the remaining hydrogen storage tank amount TANK(t) during the target period t is equal to or less than the tank capacity upper limit _THL .

Equation 37 shows that the total input power TatalP _WE (t) of the hydrogen production device 42 from the target period 0 to the target period t is the sum of the total input power TatalP _WE (t-1) of the hydrogen production device 42 from the target period 0 to the target period t-1 and the input power amount P _WE (t-1) of the hydrogen production device 42.

Equation 38 indicates that the availability rate TotalRate(t _max ) of the hydrogen production device 42 from the target period 0 to tmax is equal to or greater than the lower limit R _LL of the availability rate of the hydrogen production device 42 .

Equation 39 indicates that the operation rate TotalRate(t _max ) of the hydrogen production device 42 from the target period 0 to tmax is equal to or less than the operation rate upper limit R _HL of the hydrogen production device 42 .

<Modification 2>
Instead of the constraint of Equation 17, the constraint of Equation 17A below may be used.
CO2 _Base × CO2 _Rate ≧ Total _CO2 (t) / Total _H2 (t)
... (Formula 17A)

Equation 17A shows that for each target period t from 0 to tmax, the amount of CO2 emissions per ¹ Nm3 during hydrogen production from target period 0 to t, Total _co2 (t)/Total _H2 (t), is less than the target value CO2 _Base × CO2 _Rate of the weight [kg] of CO2 generated when ¹ Nm3 of hydrogen is produced by the hydrogen production device 42.

<Modification 3>
Alternatively, an actual measured value may be used instead of a predicted value as the amount of power generated by the photovoltaic power generator 21 shown in Equation 2, and the amount of power received from the power grid 6 may be determined in real time.

<Embodiment 2>
In the first embodiment, the hydrogen production system 1 is configured not to include a storage battery, but in the second embodiment, a configuration in which the hydrogen production system 1 includes a storage battery will be described.

[Overall configuration of hydrogen production system]
FIG. 5 is a diagram showing an overall configuration of a hydrogen production system according to a second embodiment of the present disclosure.
The hydrogen production system 1 shown in FIG. 5 includes a power conditioner 26 instead of the DC/AC converter 24 in the configuration of the hydrogen production system 1 according to the first embodiment, and further includes a storage battery 23 .

The storage battery 23 is connected to the DC/DC converter 22 and the power conditioner 26 via a power line, and is charged with the output power of the solar power generator 21, the voltage of which has been converted by the DC/DC converter 22. The storage battery 23 is also charged with the power received from the power grid 6, the power of which has been converted to direct current by the power conditioner 26. The storage battery 23 also discharges the charged power. The storage battery 23 includes, for example, a secondary battery such as a redox flow (RF) battery, a lithium ion battery, a molten salt battery, or a lead storage battery.

The power conditioner 26 is connected to the DC/DC converter 22 and the storage battery 23 via a power line. The power conditioner 26 converts the DC power output from the DC/DC converter 22 or the storage battery 23 into AC power and outputs it. The power conditioner 26 also converts the power received from the power grid 6 into DC power and outputs it to the storage battery 23.

The external I/F device 25 is connected to each piece of equipment (photovoltaic generator 21, DC/DC converter 22, storage battery 23, and power conditioner 26) installed in the power supply area 2 via a communication line (not shown). The external I/F device 25 is a device for connecting each piece of equipment to a device outside the power supply area 2, and transmits data acquired from each piece of equipment to the external device and provides data received from the external device to each piece of equipment. For example, the external I/F device 25 acquires output power information indicating the output of the photovoltaic generator 21 from the photovoltaic generator 21, and transmits the acquired output power information to a control device 51 (described later) installed in the control area 5. The external I/F device 25 also receives command data for controlling the charge/discharge amount of the storage battery 23 from the control device 51, and provides the received command data to the storage battery 23. This controls the charge/discharge amount of the storage battery 23.

The configuration of the control device 51 is similar to the configuration of the control device 51 according to the first embodiment shown in Fig. 2. However, some functions are different.
The control device 51 controls the storage battery 23 via the external I/F device 25 .

The emission amount acquisition unit 57 acquires the amount of CO2 emissions CO2 _Bat (t) in the production of electricity charged to the storage battery 23. In other words, the emission amount acquisition unit 57 calculates the amount of CO2 emissions CO2 Bat (t) in the production of electricity charged to the storage battery 23 in a state after the storage battery 23 has been charged, based on the amount of carbon dioxide emissions in the production of electricity charged to the storage battery 23 in a state before the storage battery 23 is charged and the carbon dioxide emissions in the production of electricity charged to the storage battery 23. The CO2 emission _{amount CO2 Bat (} t) is calculated by Equation 54 described below.

The determination unit 59 determines the amount of power received from the power grid 6, _{P Grid} (t) [kWh], based on the target values of CO2 emission amounts (CO2 _Base , CO2 _Rate ), the CO2 emission amounts CO2 _Pv (t), CO2 Grid (t) and CO2 _Bat (t), and the amount of power generated, P _Pv (t).

Hereinafter, a method for determining the amount of received power P _Grid (t) [kWh] by the determination unit 59 will be described in more detail.

For example, the determination unit 59 determines the amount of power received from the power grid 6 P Grid (t) by maximizing the objective function shown in Equation 1 under the constraint conditions shown in Equations 14 to 18 and the constraint conditions shown in the following Equations 51 _{to 58. A predetermined mathematical optimization method is used to determine the amount of power received P Grid (} t).

Next, each formula will be explained.
<<Parameters>>
Charge/discharge efficiency [%/100]: μ ... (Formula 40)
SOC upper limit [kWh]: SOC _HL ... (Equation 41)
SOC lower limit [kWh]: SOC _LL ... (Equation 42)

Equations 40 to 42 show the parameters required to calculate the objective function or constraints.

Equation 40 shows the charge/discharge efficiency [%/100] of the storage battery 23, taking into account the conversion loss in the power conditioner 26.

Equation 41 represents the upper limit SOC _HL [kWh] of the SOC (State of Charge) of the storage battery 23 .

Equation 42 represents the lower limit SOC _LL [kWh] of the SOC of the storage battery 23 .

<<Variables>>
Battery AC output power [kWh]: P _{Bat_ac} (t) ... (Equation 43)
Storage battery DC output power [kWh]: P _{Bat_dc} (t) ... (Equation 44)
Battery discharge operation: S _{Bat_dcrg} (t) [0, 1] ... (Equation 45)
Battery charging operation: S _{Bat_crg} (t) [0, 1] ... (Equation 46)
Battery remaining capacity [kWh]: SOC(t) ... (Equation 47)
CO2 emission from the battery [kg/kWh]: CO2 _Bat (t) ... (Equation 48)
CO2 emission amount due to battery power [kg]: _{COutput_Bat} (t)... (Equation 49)
CO2 emissions from grid and solar power [kg/kWh]: CO2 _in (t) ... (Equation 50)
Equations 43 to 50 show the variables used in calculating the objective function or constraints.

Equation 43 shows the amount of power P _{Bat — ac} (t) [kWh] of AC power that is output from the storage battery 23 and converted by the power conditioner 26 during the target period t.

Equation 44 represents the amount of DC power P _{Bat — dc} (t) [kWh] output from the storage battery 23 during the target period t.

6 is a diagram showing the relationship between the amount of power P _{Bat — ac} (t) and the amount of power P _{Bat — dc} (t). The discharge power from the storage battery 23 is taken as a positive value, and the charge power to the storage battery 23 is taken as a negative value. The amount of power P _{Bat — dc} (t) output from the storage battery 23 is converted to the amount of AC power P _{Bat — ac} (t) at a charge/discharge efficiency μ.

Equation 45 is a variable S _{Bat_dcrg} (t) that indicates whether the storage battery 23 is in discharging operation or not. When the variable S _{Bat_dcrg} (t) is 1, it indicates that the storage battery 23 is in discharging operation, and when it is 0, it indicates that the storage battery 23 is not in discharging operation.

Equation 46 is a variable S _{Bat_crg} (t) that indicates whether the storage battery 23 is in charging operation or not. When the variable S _{Bat_crg} (t) is 1, it indicates that the storage battery 23 is in charging operation, and when it is 0, it indicates that the storage battery 23 is not in charging operation.

Equation 47 shows the remaining capacity SOC(t) [kWh] of the storage battery 23 during the target period t.

Equation 48 shows the amount of CO2 emission CO2 _Bat (t) [kg/kWh] during the production of electricity output from the storage battery 23 during the target period t.

Equation 49 shows the amount of CO2 emission C _{Output_Bat} (t) [kg] during the production of electricity output from the storage battery 23 during the target period t.

Equation 50 shows the amount of CO 2 emissions CO 2 _in (t) [kg/kWh] in the production of electricity, which is the sum of the power received from the power grid 6 and the power generated by the solar power generator 21 .

<<Constraints>>
P _{Bat_dc} (t) = S _{Bat_dcrg} (t) × (P _{Bat_ac} (t) / μ)
+ S _{Bat_crg} (t) × (P _{Bat_ac} (t) × μ)
... (Equation 51)
SOC(t)=SOC(t−1) _{−PBat_dc} (t−1) ... (Equation 52)
CO2 _in (t) = (CO2 _Grid (t-1) x P _Grid (t-1)
+ CO2 _Pv (t-1) x P _Pv (t-1)
/(P _Grid (t-1) + P _Pv (t-1)) ... (Equation 53)
CO2 _Bat (t) = S _{Bat_dcrg} (t-1) × CO2 _Bat (t-1)
+ S _{Bat_crg} (t-1) x
{(CO2 _Bat (t-1) x SOC (t-1)
−CO2 _in (t−1) × P _{Bat_dc} (t−1)) / SOC (t) ... (Equation 54)
C _{Output_Bat} (t) = CO2 _Bat (t) x P _{Bat_ac} (t)
... (Equation 55)
S _{Bat_dcrg} (t) + S _{Bat_dcrg} (t) = 1 ... (Equation 56)
SOC(t)>=SOC _LL ... (Equation 57)
SOC(t)<= _SOCHL ... (Equation 58)

Equations 51 to 58 show the constraints for maximizing the objective function shown in equation 1.

Equation 51 indicates that the amount of DC power output from the storage battery 23 during the target period t, P _{Bat_dc} (t), is the sum of the amount of AC power during discharging, P _{Bat_ac} (t), divided by the charge/discharge efficiency μ, and the amount of AC power during charging, P _{Bat_ac} (t), multiplied by the charge/discharge efficiency μ.

Equation 52 indicates that the remaining capacity SOC(t) of the storage battery 23 in the target period t is a value obtained by subtracting the output power P _{Bat — dc} (t−1) from the remaining capacity SOC(t−1) of the storage battery 23 in the target period t−1.

Equation 53 shows that the CO2 emissions CO2 _in (t) during the target period t is the value obtained by dividing the CO2 emissions during the production of the power received from the power grid 6 and the power generated by the solar power generator 21 by the sum of the received power and the generated power.

Equation 54 shows that the CO2 emissions CO2 _Bat (t) of the charging power of the storage battery 23 during the target period t is the sum of the CO2 emissions in producing the output of the storage battery 23 during discharging and the CO2 emissions in producing the output of the storage battery 23 during charging.

Equation 55 shows that the amount of CO2 emission C _{Output_Bat} (t) during the production of electricity output from the storage battery 23 in the target period t is the product of the amount of CO2 emission CO2 _Bat (t) and the amount of output power P _{Bat_ac} (t) of the storage battery 23.

Equation 56 indicates that during the target period t, the storage battery 23 performs discharging or charging operation.

Equation 57 indicates that the remaining battery capacity SOC(t) of the storage battery 23 during the target period t is equal to or greater than the lower limit SOC _LL .

Equation 58 indicates that the remaining battery capacity SOC(t) of the storage battery 23 during the target period t is equal to or less than the upper limit SOC _HL .

Figure 7 is a diagram showing an example of a screen display by the display control unit 61 according to the second embodiment of the present disclosure.

The display screen shown in FIG. 7 is similar to the display screen according to embodiment 1 shown in FIG. 3. However, information about the storage battery 23 has been added.

In other words, it is shown that the power charged from the power grid 6 and the solar power generator 21 to the storage battery 23 is R [kW]. Note that when power is discharged from the storage battery 23, the arrow points in the opposite direction and the discharged power is displayed.

It also shows that the amount of CO2 emissions in producing the electricity charged to the storage battery 23 is zzz [kg/kWh].

[Processing flow of the control device 51]
FIG. 8 is a flowchart showing an example of a processing procedure of the control device 51 according to the second embodiment of the present disclosure.

The target value acquisition unit 56 reads out the target values of the CO2 emission amount (CO2 _Base , CO2 _Rate ) from the storage unit 55 (S1).

The emission acquisition unit 57 reads out the CO2 emission amount CO2 _Grid (t) in the production of the received power from the power grid 6 from the storage unit 55 (S2).

The emission acquisition unit 57 reads out the CO2 emission amount CO2 _Pv (t) in the production of the power generated by the solar power generator 21 from the storage unit 55 (S3).

The emission acquisition unit 57 calculates the amount of CO2 emitted CO2 _Bat (t) in the production of the electricity charged to the storage battery 23 according to Equation 54 (S11).

The generated power amount acquisition unit 58 reads out the generated power amount P _Pv (t) of the solar power generator 21 from the storage unit 55 (S4).

The determination unit 59 determines the amount of power received from the power grid 6 P Grid (t) by maximizing the objective function shown in Equation 1 under the constraint conditions shown in Equations 14 to 18 and the constraint conditions shown in Equations 51 to ₅₈ (S12).

The command transmitting unit 60 determines the amount of input power _PWE (t) to the hydrogen production device 42 based on the amount of received power _PGrid (t), and transmits a command including the amount of input power _PWE (t) to the external I/F device 44 (S6).

[Effects of the second embodiment]
As described above, according to the second embodiment of the present disclosure, even in a configuration including the storage battery 23, it is possible to determine the amount of CO2 emissions during hydrogen production in accordance with a target value while making good use of the power generated by the solar power generator 21 and the power received from the power grid 6 in a balanced manner.

Furthermore, according to equation 54, even when both generated and received power are charged to the storage battery 23, the amount of CO2 emissions in the production of the electricity charged to the storage battery 23 can be accurately calculated.

[Additional Notes]
Some or all of the components constituting the control device 51 may be configured from one or more semiconductor devices such as a system LSI.

The above-mentioned computer program may also be distributed by recording it on a computer-readable non-transitory recording medium, such as a HDD, CD-ROM, or semiconductor memory. The computer program may also be distributed by transmitting it via a telecommunications line, a wireless or wired communication line, a network such as the Internet, or data broadcasting.

The control device 51 may also be realized by multiple computers or multiple processors.

In addition, some or all of the functions of the control device 51 may be provided by cloud computing. In other words, some or all of the functions of the control device 51 may be realized by a cloud server.

Furthermore, at least some of the above embodiments and variations may be combined in any manner.

The embodiments disclosed herein should be considered to be illustrative and not restrictive in all respects. The scope of the present disclosure is indicated by the claims, not by the meaning described above, and is intended to include all modifications within the meaning and scope of the claims.

REFERENCE SIGNS LIST 1 Hydrogen production system 2 Power supply area 3 Piping area 4 Hydrogen production area 5 Control area 6 Power system 7 Power receiving point 21 Solar power generator 22 DC/DC converter 23 Storage battery 24 DC/AC converter 25 External I/F device 26 Power conditioner 31 Valve 32 Hydrogen storage tank 33 Valve 34 Valve 35 External I/F device 41 AC/DC converter 42 Hydrogen production device 43 Valve 44 External I/F device 51 Control device 52 Display device 53 Control unit 54 Communication unit 55 Memory unit 56 Target value acquisition unit 57 Emission amount acquisition unit 58 Generated power amount acquisition unit 59 Determination unit 60 Command transmission unit 61 Display control unit 71 Graph 72 Graph

Claims (10)

A control device for controlling a hydrogen production device that produces hydrogen using input power generated by a generator that uses renewable energy and input power from a power grid,
a target value acquisition unit that acquires a target value of a carbon dioxide emission amount during hydrogen production by the hydrogen production device;
an emission acquisition unit that acquires carbon dioxide emission amounts in the production of the generated power and the received power;
a power generation amount acquisition unit for acquiring the amount of power generated by the generator;
a determination unit that determines an amount of power received from the power grid based on the target value, the amount of carbon dioxide emission in the production of the generated power and the received power, and the amount of generated power. The control device according to claim 1, wherein the determination unit determines the amount of received power by optimizing a predetermined objective function under the constraint that the sum of the amount of carbon dioxide emissions in the production of the generated power and the received power input to the hydrogen production device does not exceed the target value. The control device further controls a storage battery that is charged with the generated power and the received power,
The emission acquisition unit further acquires an amount of carbon dioxide emission in the production of charging power for the storage battery,
3. The control device according to claim 1, wherein the determination unit determines the amount of received power based on the target value, the amount of carbon dioxide emission in the production of the generated power, the received power, and the charging power, and the amount of generated power. The control device according to claim 3, wherein the emission amount acquisition unit calculates the amount of carbon dioxide emissions in the production of the electricity charged to the storage battery in a state after the storage battery is charged, based on the amount of carbon dioxide emissions in the production of the electricity charged to the storage battery in a state before the storage battery is charged and the amount of carbon dioxide emissions in the production of the electricity charged to the storage battery. The control device according to any one of claims 1 to 4, further comprising a display control unit that displays on a screen the ratio of carbon dioxide emissions in the production of electricity consumed in hydrogen production by the hydrogen production device relative to the target value. The control device according to claim 5, wherein the display control unit further causes the generated power and the received power input to the hydrogen production device to be displayed on the screen. The control device according to claim 6, wherein the display control unit causes the screen to display the amount of carbon dioxide emissions in the production of the generated power and the received power. A control method for controlling a hydrogen production device that produces hydrogen using input power generated by a generator that uses renewable energy and input power received from a power grid, comprising:
The computer acquires a target value of carbon dioxide emission during hydrogen production by the hydrogen production device;
A step in which the computer acquires carbon dioxide emission amounts in the production of the generated power and the received power;
The computer acquires an amount of power generated by the generator;
The control method includes a step of determining, by the computer, an amount of power received from the power grid based on the target value, the amount of carbon dioxide emission in the production of the generated power and the received power, and the amount of generated power. A computer program for causing a computer to function as a control device for controlling a hydrogen production device that produces hydrogen using input power generated by a generator that uses renewable energy and input power received from a power grid,
The computer,
a target value acquisition unit that acquires a target value of carbon dioxide emission during hydrogen production by the hydrogen production device;
an emission acquisition unit that acquires carbon dioxide emission amounts in the production of the generated power and the received power;
a power generation amount acquisition unit that acquires the amount of power generated by the generator; and
a computer program that causes the computer to function as a determination unit that determines an amount of power received from the power grid based on the target value, the amount of carbon dioxide emission in the production of the generated power and the received power, and the amount of generated power. A generator that uses renewable energy,
a hydrogen production device that produces hydrogen using the electric power generated by the generator and the electric power received from a power grid as input power;
A hydrogen production system comprising: a control device according to any one of claims 1 to 7, which controls the hydrogen production device.

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